Humidity control system



Sept. 12, 1933. W, E STARK 1,926,462

HUMIDITY CONTROL SYSTEM Filed June 5, 1931 ATTORNEYS Patented Sept. l2, A1933 PATENTv OFFICE HUltIEDITY CONTROL SYSTEM wiuet E. stark, East cleveland, ohio, assignor, by mesne assignments, to The Bryant Heater vCompany, Cleveland, Ohio, a corporation of Ohio Application v.lune 5, 1931. Serial No. 542,369

9 Claims.

'Ihis invention relates to improvements in humidity control systems for use primarily in connection with hot air heating systems.

One of the objects of the invention is the prov vision of a means for supplying water vapor to the air entering the rooms to be heated so long as the humidity of the air in those rooms remains below a predetermined value and to automatically interrupt the operation of such means when the humidity rises above a predetermined level, and to automatically begin the operation again when the humidity falls below the predetermined level.

Another object is the provision in this connection of a vaporizer consisting of a water vessel containing a steam coil and the use of a shutoff valve in the return or condensation line. from the steam coil, whereby the water of condensation gradually lls the coil and in this manner prevents the further admission of steam tothe coil.

Another object is the provision of a system wherein the automatic control valve may be of small size and so located in the system as not to be subject to high heat.

Other objects and features of novelty will appear as I proceed with a description of that embodiment of the invention which, for the purposes of the present applicatioml have illustrated in the accompanying drawing, wherein Figure l is an elevational view, partly in vertical section, showing a hot air heating apparatus in which heat is supplied by a steam radiator arranged in the path of travel of the air, and wherein a vaporizer embodying a steam `coil is utilized for humidifying the air, the radiator and steam coil being connected up to a steam boiler.

Fig. 2 is a view of the same partly in end elevation and partly in vertical section upon the line 2-2 of Fig. 1.

Fig. 3 is an elevational view on a larger scale illustrating a form of humidity control mechanism which may be employed in connection with the invention, and

Fig. 4 is a detail view, partly in vertical section, of the shut-off valve in the return pipe of the steam coil.

1n the drawing I have shown at 10 a boiler which may be of anyV desired type, although by Way of example Ihave illustrated herein a gas boiler having a gas manifold l1 and a series of cocks 12 controlling burners within the casing. The steam generated in the boiler is delivered through connections 13 into a common delivery pipe 14 which leads to a header 15 inside a casing 16. The header 15 comprises part of a steam radiator 17 of any desired form, but in this case having a series of parallel pipes with sheet metal ns attached thereto for heat radiation; the pipes being supported at one end in the header l5 and at the other end in a second header 18. Angle bar brackets 19 attached to the casing walls may 60 be used for supporting the radiator. A return pipe orl condensation pipe for 'the radiator is shown atA 20 as connected with the header 18 and passing back through the casing 16 to a T 21 to which is attached an air venting valve 22 of 65 usual construction, that is to say one which opens automatically to permit the discharge of air but which closes through thermostatically controlled means when steam comes into contact with the thermostat. In the casing 16 below the radiator 17 l mount a water vessel 23, which may be in the form oi ay sheet metal pan open at the top. This vessel may be conveniently supported upon angle brackets 24 secured to the end walls of the casing. The level of Water in the vessel 23 may be maintained, as indicated in the' drawing, by any suitable oat valve mechanism located in a small housing 25 outside the casing, the inlet pipe from the house water system being indicated at 26, and the pipe connecting the automatic valve with the vessel 23 being shown at 27. 28 is an overflow pipe which prevents flooding of the apparatus in the casing 16 in the event of any failure of the 'automatic Water valve to function properly.

Within the vessel 23 there is a steam coil 29 having an upwardly directed inlet pipe 30 which is connected into the steam 'delivery pipe 14 by means of a T 31. The steam coil also has a downwardly directed return or condensation pipeY 32. Connected with the lower end of pipe 32 there is a short horizontal condensation pipe 33 in which is mounted a shut-ofi valve 34 which is adapted to descend to closed position by gravity and to be raised to open position by the solenoid of an electromagnet, indicated at 35. The horizontal pipe 33 connects the steam coil return pipe 32 with a radiator return `pipe 36 which extends downwardly from T 21 and at its lower end has ahorizontal section 37 running into the boiler. The upper end of condensation pipe 32 is connected with a T 38 by means of which it communicates not only with the steam coil 29 but also with an upwardly extending pipe 39 through 105 which air may be discharged from the steam coil into the pipe 26 and carried thence to the air vent valve 22.

1n the casing 16 some distance below the water vessel 23 there is a horizontal partition 46. The no chamber provided below this partition is con-= nected at 41 with air return conduits leading generally from the premises being heated. Within this chamber there is a fan housing 42 open at its ends to the interior of the chamber and open at the top into the interior of the casing 16. Extending through the fan housing 42 there is a shaft 43 supported in bearings' 44 and carrying within the housing 42 a centrifugal fan 45. On one end of shaft 43 there may be mounted a pulley 46 over which runs a belt 47 driven by an electric motor 48. By this means air is taken from the return conduits of the heating system and forced through the chamber 16 past the water vessel 23 and through the radiator 17 and out through an opening 49 to which areconnected the heating pipes leading to the various rooms oi the premises to be heated.

In one of the rooms to be heated I install an automatic humidity control devicel indicated generally .at 59, and shown in detail in Fig. 3. This device comprises a strip or ribbon 51 of paper which runs over four fixed pins 9, and expands and contracts with variations in the humidity of the air in the room in which it is located. One end of this ribbon is attached to a lever 52 mounted to pivot about a pin 53. The position of this lever may be adjusted within certain limits by means of a screw 54 with a lmurled head which is threadably mounted in the lever and extends through an eye 55 mounted on the base of the device. Collars 56 and 57 are pinned to the screw 54 on opposite sides of the eye 55, so as to prevent longitudinal movement of the screw with respect to the eye. The opposite end of 'the ribbon 51 is secured to a lever 58 that is adapted to swing upon a fixed pin 59. At the opposite end of this lever there is a spring 69 tending to so move the level. as to hold the ribbon 51 taut. The lever 58 carries a depending arm 61 with a bifurcation at its lower extremity straddling a pin 62 on a clamp 63 which is mounted to swing about a fixed pivot 64. The clamp 63 holds a mercury tube 65 containing a globule 66 of mercury. Sealed into one end of this tube there areterminals 67 and 68 of flexible electric conductors 69 and 70, the opposite extremities of which are mounted upon binding posts 71 and 72. The opposite ends of these posts are connected to electric conductors 73 and 74. One of these conductors, 74, leads to a binding post on the electromagnet 35,/,and the other conductor 73 extends to a line wire 75. From the other binding post on electromagnet 35 a conductor 76 extends to the second line wire 77.

Operation.--I.et it be assumed that the heating system is an automatic one, and that the temperature controlling mechanism (not shown) located in the premises being heated calls for Y heat, resulting in the admission of gas to manifold 11 and thence to the burners in the boiler 10.

Let it be further assumed that the moisture content of the air in the premises being heated is up to or above the desired minimum, in which event the globule 66 of mercury will be in the right-hand end of the tube 65, as shown in Fig. 3. Under this condition there will be no electric connection between terminals 67 and 68, and electric valve 34, 35 will therefore be closed. Let it be assumed also that the action of the temperature control, which admitted gas to the boiler 10, at the same time started motor 48, driving fan 45, auto matic operation of this kind being well known in the art. l

The burning of gas in the boiler 10 causes the formation of steam which is fed by delivery pipe 14 into radiator 17. IThe air drawn from the premises by thefan 45 through inlet opening 4l is blown across the heat conducting fins of the radiator 17, abstracting heat from them and condensing the steam in the radiator. The heated air is then blown out through outlet 49 to the premises to be heated. The water of condensation thereby formed in the radiator 17 flows by gravity through pipe 20 and pipes 36 and 37 back to the boiler. Any air that might have been contained in the boiler or in the radiatorelement prior to the admission of gas to the boiler is vented out of the system through air vent valve 22.

fi small amount of steam from pipe 14 also flows through pipe 30 into steam coil 29. Air contained in the latter pipe at the time steam enters it is expelled through pipes 39 and 20, and escapes through air vent valve 22. The water resulting from the condensation of steam in steam coil 29 trickles down through the return pipe 32 into horizontal pipe 33, where it is blocked by valve 34 which', under the assumed conditions, is closed. This water backs up behind valve 24, quickly fills the comparatively small bore pipe 32, and then the steam coil 29. The pipe 39 will also be filled. As soon as these pipes are thus filled with water, no more steam can enter steam coil 29, and therefore there will be no evaporation of the water contained in vessel 23. In fact this water, which was heated by the steam in the coil before the condensation thereof, will thereafter rapidly cool oil', owing to the flow of cool air over the walls of vessel 23.

Now let it be assumed that the moisture content of the air in the room in which the humidity control apparatus 50 is located drops below the predetermined minimum. This causes paper ribbon 5l to contract, and since the lower end of this ribbon is fixed in the extremity of lever 52, which is immovable, the shortening of the ribbon 51 will cause the swinging of lever 58 about pin 59 in a clockwise direction, this movement being resisted but not prevented by the tension of spring 60. When lever 58 rotates thus in a clockwise direction, the bifurcation at the lower end of depending arm 61 also rotates in a clockwise direction, resulting in the rotation of mercury tube about pin 64 in a counterclockwise direction. This rotation, though slight, will bc sufficient in amount to cause the globule 66 of mercury to run to the left end of tube 65, which will result in the completion of an electric circuit across the terminals 67 and 68, and including the line wires 75 and 77 and the conductors 73, 74 and 76 extending to the coil of electric valve 34, 35. The solenoid, to which the valve 34 is attached, is thereby raised and the valve is opened. When electric valve 34 opens, the water which is dammed up back of it, fills the steam pipe 29, trickles down through return pipes 32 and 33 and is delivered to the boiler through pipe 37.

As soon as the water drains out of steam coil 29 and this coil is filled with steam from pipes 14 and 30.- the water in vessel 23 becomes rapidly heated and evaporation of the watenin the vessel begins quickly and continues at a rapid rate. The vapor rising from the surface of the water in this vessel is picked up by the air rushing past it and is delivered through outlet 49 and connecting ducts to the premises being heated. As the amount of water in vessel 23 is diminished, due to evaporation, it must be replenished, preferably from the city water supply connected to the pipe 26 through the action of a float feed valve or the like contained is casing 25.

The circulation of the moist warm air through the rooms being heated brings the moisture laden air into contact with' the paper ribbon 51 of the humidity control device shown in Fig. 3. The ribbon absorbs moisture and tends to elongate, As it elongates spring 60 takes up the elongation,

, causing the rotation of lever 58 about pin 59 in a counterclockwise direction. This in turn causes the rotation of mercury tube 65 about pin 64 in a clockwise direction through the agency of depending arm 61, the bifurcation at the lower extremity thereof, and the pin 62. When the rotation of the mercury tube in the clockwise direction has progressed far enough, the globule 66 of mercury will run to the right-hand end of the tube, breaking the electrical connection between terminals 67 and 68. The coil of electromagnet is thus deenergized, and the solenoid with the valve piece 34 drops, thereby closing the valve and blocking the return pipe connections from the steam coil, so thatthe process of damming up water back of the valve 34 and filling the steam coil 29 immediately starts and is completed within a short time, resulting in a complete cessation of evaporation of the water contained in tank 23.

The alternate opening and closing of electric valve 34, 35 continues as long as there are variations in the moisture content of the air in the room in which humidity control mechanism is installed, that is so long as the variations alternate above and below the value which it is desired to maintain. When the temperature requirements of the premises being heated are satisfied, the gas to manifold l1 is turned off and the motor 48 stopped, so that the delivery of steam to the radiator 17 ceases and the forced draft ofair also ceases. There is then no steam available for steam coil 29. This however is of no practical disadvantage, because the moisture requirement of heated premises is roughly proportional to the heat requirement, and the controlling system herein disclosed serves merely to make the moisture production exactly proportional to the moisture requirement.

Owing to the fact that the return pipes 32 and 33 may be of relatively small bore, the valve 34 may be small, whereas if a valve in the inlet to the steam coil were employed it would have to be of larger capacity. Furthermore the valve 34 is never subjected to high heat as would be the case were the control valve located in the steam inlet. Hence the valve as located in my apparatus functions easily and certainly, requires no servicing, and enjoys long life.

The hot air heating system herein described is of novel construction, being disclosed and claimed in a separate application, Serial No.542,370, led by me of even date herewith, and is adopted for illustration herein because of the special adaptability of my humidity control to a system in which steam is employed for heating the air. However, it will be appreciated, that the present invention may be employed in ordinary hot air systems, provided that means is provided for generating steam to be fed to the steam coil of the vaporizing apparatus. It will also be understood that I have necessarily gone somewhat into detail in other respects in order to explain fully the particular embodiments of the invention herein illustrated, but I desire it to be understood that such detail disclosures are not to be .construed as amounting to limitations, except as they may be included in the appended claims.

steam coil gradually lls with water of condensad tion, preventing the admission oi further steam to the coil.

2. In apparatus of the class described, a water vessel, a steam coil in said vessel, means for delivering steam to said coil, a condensation pipe connected with said steam coil, and means controlled by the moisture content of the air in a room for blocking said condensation pipe when the moisture content of the air in said room rises above a predetermined point, whereby the steam coil lls with water of condensation, preventing the admission of further steam to the coil.

3. In apparatus of the class described, a water vessel, a steam coil in said vessel, means for delivering steam to said coil, a condensation pipe connected with said steam coil, a shut-oi valve in said condensation pipe, electrical means for operating said valve, an electric switch located in a room to be heated, means controlled by the moisture content of the air in said room for opening and closing said switch and an electrical circuit connecting said switch with said valve operating means.

4. In a hot air heating system, an air conduit, a water vessel mounted therein, a steam coil in said vessel, a boiler for supplying steam to said coil, delivery and return pipes connecting said boiler and steam coil, a valve in said return pipe, means controlled by the moisture content in a room to be heated for closing said valve when the moisture content of the air in said room rises above a predetermined level, and for opening said valve when the moisture content descends below a predetermined level.

5. In a hot air heating system, an air conduit, a steam radiator mounted therein, a water vessel also mounted in said conduit, a steam coil in said vessel, delivery and return pipes con necting said radiator and steam coil respectively with said boiler, and means controlled by the moisture content of the air in a room to be heated for blocking the return pipe from said steam coil when the moisture content -of the air in said room rises above a predetermined level, and for opening the return pipe from said steam coil when the moisture content descends below a predetermined level.

6.- In apparatus of the class described, a Water vessel, means for delivering Water to said vessel automatically whenever' the level thereof falls below a predetermined minimum, a steam coil in said vessel, means for delivering steam to said coil, a condensation pipe connected with said steam coil, and means controlled by the moisture content of the air in a room for blocking said condensation pipe when the moisture content of the air in said room rises above a predetermined point, whereby the steam coil lls with water of condensation, preventing the admission of further steam to the coil.

7. In apparatus of the class described, a water vessel, means for delivering water to said vessel automatically Whenever the level thereof falls below a predetermined minimum, a steam coil in said vessel, means for delivering steam to said coil, a condensation pipe connected with said steam coil, a shut-01T valve in said condensation ilo pipe, electrical means for operating said valve, an electric switch located in a room to be heated, means controlled by the moisture content of the air in said room for opening and closing said switch, and an electrical circuit connecting' said switch with said valve operating means.

8. In a hot air heating system, an air conduit, a water vessel mounted therein, means for delivering water to said vessel automatically whenever the level thereof falls below a predetermined minimum, a steam coil in said vessel, a boiler for supplying steam to said coil, delivery and return pipes connecting said boiler and steam coil, a valve in said return pipe, means controlled by the moisture content in a room to be heated for closing said valve when the moisture content of the air in saidroom rises above a predetermined level, and for opening said valvevwhen the moisture content descends below a predetermined level.`

9. In a hot air heating system, an air conduit, a steam radiator mounted therein, a water vessel also mounted in said conduit, means for delivering water to said vessel automatically whenever the level thereof falls below a predetermined minimum, a steam coil in said vessel, delivery and return pipes connecting said radiator and steam coil respectively with said boiler, and means controlled by the moisture content of the air in a room to be heated for blocking the return pipe from said steam coil when the moisture content of the air in said room rises above a predetermined level, and for opening the return pipe from said steam coil when the moisture content descends below a predetermined level.

W'ILLET E. STARK. 

